Plastering and skimming are two different techniques for finishing walls. Plastering involves applying a thick layer of a plaster mixture—typically containing gypsum, lime, cement, sand, and water—to create a new surface. This process often requires multiple coats and is used for repairing significant damage or creating decorative textures. Skimming, on the other hand, is a technique that involves applying a thin layer of drywall compound or joint compound over an existing surface to smooth it out, covering minor imperfections, small cracks, or uneven textures for a polished look. Plastering is generally more costly and labor-intensive than skimming. Although some people use the terms interchangeably, they refer to different processes and materials.

Yes, you can mount a TV on plaster walls—as long as you attach it to the studs. Alternatively, you can use toggle bolts, molly bolts, or another type of hardware that’s strong enough to support a TV. 

If you aren’t comfortable with this type of project, you can hire a pro. The cost of mounting a TV to a plaster wall ranges from $25 to $600 (or more), depending on the TV’s weight, size, and other factors.

You should leave a gap between drywall sheets because they naturally expand and contract along with the building framing as temperature and humidity change. Most pro drywall installers leave a gap of about ⅛ inch between drywall sheets, allowing the sheets to expand, contract, and shift without cracking or becoming damaged. If you don’t leave enough gaps between slabs, the edges will press against each other when they expand, and the pressure can cause visible cracks.

All plaster walls will crack over time due to normal house settling and expansion and contraction from temperature and moisture changes. Small, thin hairline cracks are generally not serious and are mostly a cosmetic issue. However, larger or more significant cracks can indicate structural problems.

Here's how to tell the difference:

• Cosmetic Cracks: Cracks that are 0.5 cm (0.2 inches) or thinner are typically cosmetic.

• Structural Cracks: Cracks wider than 0.5 cm, excessive or deep cracks, multiple cracks in the same area, or cracks that span around corners can signify a structural or foundation issue. Cracks along the joints where walls meet the ceiling also warrant attention.

For cracks wider than 0.5 cm, structural repair is needed. If a crack is 2.5 cm (1 inch) or wider, or if you notice any signs of a structural problem, it is best to contact a plaster repair professional to assess the damage.